In Florida, a police cadet with dreams of protecting and serving suddenly goes missing. Could a conversation she had with her best friend hours before her disappearance be the key to solving this case?

Kelly Rothwell, 35, was a spiritual and adventurous soul. She was athletic, smart and had traveled the world. She spontaneously moved from Colorado to Indian Rocks Beach on Florida's Gulf Coast.

Donna Scharrett, Kelly Rothwell's best friend, remembers the day they met,

"I met her at a beach meditation circle," said Scharrett. "She says 'Hi, I'm Kelly,' and in that moment I knew that I had met one of my best friends."

Life in Florida was good, and seemed to get even better when Kelly met a man vacationing there. That man was attractive, charming and swept Kelly off her feet. That man was David Perry.

"At a salad bar at a restaurant, he offered her pepper. She was by herself and he went and sat down with her," said Lauren Rothwell, Kelly's sister.

From salad to sweethearts in almost 60 seconds flat, the relationship moved fast. Within weeks, David moved into Kelly's condo.

"She just kept saying 'I know this sounds crazy but it feels right,' so I just tried to be supportive," said Lauren.

David Perry, 46, originally from New York, was a retired New York state corrections officer.

Lauren met David shortly after he moved in.

"I liked him," Lauren said. "He was very friendly and charming."

But good first impressions morphed into questionable second ones. Turns out David was militant -- some would say obsessive-compulsive -- about cleanliness.

"He vacuumed about three times a day, the lines in the carpet had to go a certain way," said Lauren. "The day we left, my sister -- and I think this was just in fear of not having to deal with him -- had us clean the bedroom, the bathroom, spot-check everything. I didn't understand how she, this fast, became this other person. She was just constantly worried about him."

Many say David was becoming increasingly possessive and controlling.

Donna Scharrett says he shut down her social media accounts, read her emails and isolated her from friends and family.

"Kelly told me that she could feel that he was closing in on her," said Donna.

Then, three years into their relationship, Kelly made a surprising life decision: She enrolled in the police academy.

"She was a motivator," said John Dressback, director of the Southeastern Public Safety Institute of St. Petersburg College. "She never quit, she never complained. The students looked up to Kelly."

Four weeks from graduation, at the academy Kelly was happy. At home, with David, she was not. Kelly decided she'd had enough. But leaving wasn't going to be easy.

It was a cool evening in March, and Kelly was ready to have a fun girls' night at Donna's. But Donna says David had other plans.

"She wasn't at my house two minutes and her text message goes off," said Donna. "A couple of minutes goes by, text again, text again, text again. We probably spent two hours inside my house and 80-90 percent of it was Kelly on the phone with him.

"She was saying 'I told you I'm through with this, I'm done with this, Dave, I told you it's over,'" said Donna.

What David didn't know was that Kelly had already found a new place to live, and she would be leaving him and moving in the next day.

"He said 'I'm going to bed, you have a good time with Donna, I'm sorry I ruined your weekend,'" said Donna.

They leave to go grab drinks. But once in Donna's truck, Kelly says: "I need you to lock your door, and I'm like, 'What's going on?' And she's like 'That car over there, that's Dave.' I'm like, 'He doesn't know where I live, how did he get here?' And she goes 'He must have followed me.'"

Donna says as she and Kelly drove off, David was not far behind. He was following them. Eventually they were able to lose David in traffic. Safe back at the house, Donna couldn't shake what had happened.

"I'm going 'This is not normal, Kel, you need to call somebody. He's stalking you,'" said Donna. "She goes 'No it's going to be OK, I can take care of this, don't worry about it.'"

Kelly thought David had gone home but he hadn't. He was back. His car was parked at Donna's with a black shirt hanging in front of the windshield.

"She walked straight up to that car and she said 'Well would you look at that, Dave's here,' and I just got cold chills," said Donna. "And she yanked it open and said 'What the hell are you doing, Dave?' And I'm standing there watching this. And he's like, 'Kelly, but I love you, I promise I'll change.' 'No, it's over, Dave, I am done, and he said 'Fine. Fine.'"

David peeled off into the night. Donna was shell-shocked. Kelly tried to make light of it, until they went to bed that night.

"I could tell she was crying and she goes 'I'm scared, I'm really changing my life, but what if he has a hard time with this, how am I gonna help him through this?'" said Donna. "That's what she was afraid of."

And that's not all.

"He told her 'If you ever leave me I will throw your dead body in the Gulf and they will never find you,'" said Donna.

The next day was going to be a life-changing one: Kelly was going to leave David for good. Kelly and Donna had lunch. In the parking lot, as they said their goodbyes, Donna pleaded with Kelly not to go see David alone.

"I grabbed her hands and said 'Kelly, please, please, I'm begging you, let me follow you,' and she pulled her hand back, strong and fierce, and said 'No, I don't want you to come, I got this,'" said Donna.

A few hours later, something seemed off when Donna got a text from Kelly, a text that didn't sound like her friend at all, a text Donna suspects was sent by David. The next day, Donna becomes even more concerned when she receives a troubling call from the cadet Kelly had plans with the night before, who said Kelly never showed up.

After many failed attempts to get in touch with Kelly, Donna calls the Pinellas County Sheriff's Office, requesting a welfare check on Kelly. When detectives arrived, the door was locked, so they used force to enter the home.

Kelly isn't there. Kelly Rothwell had last been seen on March 12, 2011.

Detectives talk to neighbors who report sounds they heard coming from the couple's condo.

"Neighbors did hear a loud banging, and vacuuming right after that," said Pinellas County Sheriff's Det. Amy Plourde.

Deputies quickly turn their attention to David Perry, and are anxious to talk to him. But he's nowhere to be found.

David Perry calls the director of the police academy where Kelly is a cadet at 8 a.m.

"He asked me was Kelly in class, and I said I couldn't give him that information," said John Dressback, director of the Southeastern Public Safety Institute of St. Petersburg College. "I knew that he was trying to cover his tracks, make it appear that he was the boyfriend who was trying to find his girlfriend. I knew that this was not legit.

"But I told him 'You need to speak with the Pinellas Sheriff's Office, they're trying to contact you, and it appears you've been avoiding them,'" said Dressback. "He said 'I don't know what you're talking about, and I'm not calling the sheriff's office,' and then he hung up."

When deputies were finally able to get a hold of David Perry, he was on the road, driving home to New York.

"I could tell something was not right," said Pinellas County Sheriff's Det. Michael Bailey (Ret.). "He was extremely erratic on the phone, very evasive, didn't want to answer any questions, could not wait to get off the phone. So at that point we knew that there was something to it."

When Kelly Rothwell's family learned she was missing, Kelly's sister Lauren immediately called David.

"I said 'Hey, where are you?' He said 'I'm in New York, what is going on?' Like he had no idea why I was calling," said Lauren. "I said 'Where is Kelly?' He said 'Oh, I don't know. Maybe she's in Utah.' Nothing he was saying was making sense, so I hung up on him, and that's when I knew right away that he had killed her."

David Perry hired an attorney and refused to answer any more questions from law enforcement. For the time being, their hands were tied.

As the investigation went on, more disturbing clues were discovered. Kelly's police cadet study materials were found in the dumpster near the condo. And Kelly's car was found two miles from the house.

"She did not leave that home alive that day," said Det. Amy Plourde.

Although detectives had no body, they believed, based on their investigation, Kelly Rothwell had been murdered.

"We know that Kelly was murdered. We know that David Perry killed Kelly Rothwell," said Det. Amy Plourde.

Investigators say they have a few theories, but Kelly ending their relationship is the most probable one.

For his part, David Perry hired an attorney, and has refused to answer any questions from law enforcement.

"He is the only person who is not being cooperative in this," said Bailey.

David Perry was back in his hometown of Elmira, New York, and seemed to be starting over. He even married a woman from Hawaii and took her last name. What he didn't know was in two short months, his luck would change.

"We were contacted by the Pinellas County Sheriff's Office regarding a tip they received," said New York State Police Investigator Eric Hurd.

The New York State Police received a tip and were now looking at David Perry stemming from his days as a prison guard at Elmira Correctional Facility, and something called a "red dot."

"A 'red dot' is physical force by guards involving an inmate. That's what the guards called it," said Steuben County District Attorney Brooks Baker.

And sometimes guards get hurt during those altercations. Baker says Perry had planned to use a red dot incident to fake an injury and make some money.

"He knew what he had to do to go out on retirement, he knew what his benefits would be," said Baker. "He said 'The next one that happens, I'm outta here.'"

Then the next one happened.

"There's an incident in this cell, David Perry is there, but he is certainly not injured," said Baker.

"He's making close to half a million dollars," said Baker. "He was enjoying life and apparently spending some time down in Florida. He's wind-surfing, lifting weights and doing things that disabled people can't do."

As part of the their investigation, New York State Police naturally wanted to interview David Perry.

"He was resistant, he didn't want to talk to them," said Baker. "He hopped in his car and left our area for a week."

"I mean clearly, it's suspicious," said Baker. "Kelly's body disappeared, that vehicle was in Florida where Kelly was, where he was, the vehicle was here, the state police wanted to look at it, he knew that, drives away for a week, comes back and it's been cleaned, and cleaned with bleach. For someone who works in corrections, who worries about blood-borne pathogens and is trained in DNA, that's the kind of thing that raises some red flags."

David Perry was eventually arrested -- not for Kelly's murder, but for grand larceny and insurance fraud. He was found guilty and sentenced four to 12 years.

But that wasn't the end of it. Almost a year later he was charged again for grand larceny, this time for the retirement benefits he fraudulently collected.

"During the search of his residence we located $120,000 in U.S. currency located underneath a dresser," said Eric Hurd.

And while in jail on the larceny charge, Perry got into a fight with another inmate.

"Someone didn't show him enough respect and he beat him up," said Brooks Baker. "He was convicted of assault and did six months in jail during this whole thing."

Perry eventually pleaded guilty to the grand larceny charge and spent less than two years for all of his sentences in prison. He is now out on parole.

David Perry has never been arrested or charged in the disappearance or murder of Kelly Rothwell.

Crime Watch Daily reached out to Thomas Reilly, David Perry's attorney, for a statement.

"I just wanted to let you know that I will not be giving an interview or commenting on behalf of David Perry, nor will he," Reilly said in a statement.

"The only person that committed this crime is David Perry," said Pinellas County Sheriff's Det. Amy Plourde.

Kelly Rothwell would have graduated from the police academy four weeks after she went missing. At the ceremony, instructors and fellow cadets fondly remembered her.

For the last several years, Kelly's friends and family have had to deal with their devastating loss while waiting for justice. Friends, family and detectives vow to never give up until David Perry is behind bars for the murder of Kelly Rothwell.